The present invention relates to a work unit positioning system and more particularly, to a differential gear transmission type multi-pitch adjustable work unit positioning system coupled to a number of work units, for example, Charge-Coupled Device work units, pitch-adjustable material suction and feeding work units, or pitch-adjustable material carrying work units, and adapted to control the positioning of the work units, the pitch among the work units, and the movement of the work units at an equal pitch.
In industrial applications, work units may be used and moved at a predetermined speed ratio. For example, in an automatic optical examination machine for examining printed circuit boards, glass substrates for Liquid Crystal Display, color filters, etc, Charge-Coupled Device work units may be arranged in line at an equal pitch to cover the whole width of the products to be examined. These Charge-Coupled Device work units are connected to respective computers. The examination resolution of the Charge-Coupled Device work units and the computing speed of the computers are fixed and not adjustable. It is not economic to install high-resolution Charge-Coupled Device work units for doing a low-resolution examination work. In this case, the yielding rate will be low. However, when low-resolution Charge-Coupled Device work units are used, they cannot execute a high-resolution examination work.
The present invention has been accomplished under the circumstances in view. The invention eliminates the aforesaid problem by means of arranging the Charge-Coupled Devices of the work units in a pitch adjustable manner to improve the applicability of the equipment to fit different examination requirements. The differential gear transmission type multi-pitch adjustable work unit positioning system comprises a linking mechanism coupled to a number of work units, for example, Charge-Coupled Device work units, pitch-adjustable material suction and feeding work units, or pitch-adjustable material carrying work units, and a driving mechanism for driving the linking mechanism to control the positioning of the work units and to move the work units at an equal pitch.